Stacking machine for flexible workpieces



Feb. 6, 'l968 D. L. ELLER ET Al. 3,367,651

STACKING MACHINE FOR FLEXIBLE WORKFIECES Filed April l2, 1966 5Sheets-Sheet l HZ CONTROL \l Feb. 6, 1968 n.1.. ELLER ET AL STACKINGMACHINE FOR FLEXIBLE WORKFIECES Fi'ed April 12, 196e 3 Sheets-Sheet 2INVENTORS L erafv /aELEL En lll Feb. 6, 1968 D. ELLER ET AL 3,357,651

STACKING MACHINE FOR FLEXIBLE WORKPIECES Filed April 12, 196e ssheets-sheet s f 26 /za f 2 y 2/A M9, ,24 rx @2 INVENTOR 3 Bfwm @WMMATTQRNEYS United States Patent Ollice 3,367,651 Patented Feb. 6, 19683,367,651 STACKING MACHINE FOR FLEXIBLE WORKPIECES Dale L. Eller,Lebanon, and Trigg R. Barton, Cleveland,

Va., assignors to Top Form-Yolande, Inc., Lebanon,

Va., a corporation of Virginia Filed Apr. 12, 1966, Ser. No. 542,008 9Claims. (Cl. 271-70) The present invention relates to automatic stackingequipment and in particular to stacking equipment for automaticallystacking llexible workpieces, such as garment components or the like,-as they issu-e from a sewing machine.

In the sewing and handling of garment components in the garment industryit is desirable that hand operations be kept at a minimum in order tomaintain a high production rate. One area which has often included ahand operation is the picking up and stacking of components after asewing machine operator has completed a number of pieces. For example, asewing machine operator who receives a bundle of garment components willperform a stitching operation on each component following which she willtransfer the components to another processing operation. It is often thepractice for the operator to permit the stitched components to progressin sequence into a -bin or the like and to subsequently interrupt thesewing operation in order to gather up and stack the components beforetransferring them to the next operation.

It is recognized in the industry that these hand opera tions andinterruptions of the sewing ope-ration are inelicient, and variousautomatic stacking equipment has been proposed. However, the proposedequipment has not proved entirely satisfactory because of its cost andcomplexity and the need for supervision to maintain it in p roperworking order under different operating conditions. One problem which isparticularly difficult to over come is the tendency of slick, highlyllexible components, such as those made of silk or rayon, to slide olfthe stacklng mechanism and otherwise avoid being properly handle-d.Another disadvantage of the prior sta-cking equipment is the common useof reciprocating elements which are not only complex in construction butalso apt to mis handle the garment components operating at high speed.

According to the objects of the present invention these disadvantages ofineilicient operation at high speed and when handling slick fabrics areovercome by providing -a special stacking member of simple constructionwhich rotates in only one direction in a manner to stack a garmentcomponent on top of another during each rotation. More specifically, thestacking member is mounted in a position such that during sequentialrotation it engages a garment component from below, lifts that componentupwardly out of its line of travel from the sewing machine and thencarries it in an arc to the exposed end of a stack, the stacking membercontinuing to rotate in the same direction so as to return to and stopat a position for engaging another garment component. The stackingmember is constructed generally as a pair of parellel spaced apart armswhich rotate about a common axis normal thereto so as to pass on eitherside of a stationary stacking table or the like while at the samedepositing and draping a garment component on top of the table.

Another feature of the present invention is the use of the abovedescribed stacking arms in conjunction with an 'endless conveyorarranged to maintain a slick, llexible garment component in a flatcondition at the time of transfer. In this arrangement the stacking armsare mounted for lrotation in planes normal to the line of travel of theconveyor, and are spaced apart a distance slightly greater than thelength of the conveyor. As a garment component of greater length thanthe conveyor moves along the conveyor there will occur a position inwhich the garment component extends beyond each end of the conveyor.When the component is in this position, the stacking arms are rotated soas to pass by the ends of the conveyor from the side opposite thegarment component and to lift the component off the conveyo-r. In aprefer-red construction the conveyor is the center one of a group ofthree conveyors disposed in end-to-end relationship, and the arms of thestacking member pas-s through the spaces between adjacent conveyors.

These and other objects and a-dvantages will become apparent from thefollowing detailed description in conjunction with the drawings inwhich:

FIGURE 1 is a side elevational view of a stacking machine embodying theprinciples of the present invention;

FIGURE 2 is a top plan view of the machine of FIG- URVE 1;

FIGURE 3 is an end elevational view looking from the left of FIGURE 1along the line 3 3;

FIGURE 4 is a simplified fragmentary view, on an enlarged scale, of partof FIGURE l;

FIGURE 5 is a schematic simplied block diagram illustrat-ing theprinciples of a control system for the stacking machine of FIGURES 1 4;and

FIGURE 6 is a schematic side elevational view of a modified form ofstacking machine.

Referring to FIGURES l, 2 and 3 there is shown a garment componentstacking machine 1l) in combination with a sewing machine table 12. Thelatter includes a horizontal generally rectangular plate 14 having acutout 16 for receiving the base (not shown) of a conventionalcommercial sewing machine 18. During use of the equipment a sewingmachine operator sits at the front, or righthand end of the table 12facing the rear, or left-hand end of the equipment as viewed in FIGURES1 and 2. In conducting sewing operations on a garment component, theoperator moves the component under 'the operating head of the sewingmachine 18 in a direction toward the rear of the table 12. Once thecomponent becomes free of the sewing machine 18 it is automaticallyconveyed away, as Aillustrated at 19, and stacked on top of the nextprevious component at a location to one side ofthe equipment.

The stacking apparatus 10 includes three horizontal endless conveyorbelts 20, 22 and 24 mounted in end-toend relationship behind the sewingmachine 18 with their upper runs substantially in the plane of the uppersurface of the table 12. The belts are driven in a direction to conveythe garment components away from the sewing machine 18 toward the rearor left end of the equipment. As a component 19 traverses the centerbelt 22 a rotatable stacking mechanism 26 lifts the component 19 olf thebelt 22 and deposits it on a stacking table 28 in a position 21, on oneside of the line of travel of the belts. The for- Wardmost belt 20 isdisposed in a cutout 29 in the sewing machine table 14 in a locationrearwardly of the cutout 16 so as to receive components 19 from thesewing machine 18. The center belt 22 is disposed with, its forward endslightly spaced from the rear end of the forwardmost belt 20. Justrearwardly of the center belt 22 is the third or rear belt 24, whoseforward end is slightly spaced from the rear end of the center belt 22.

Each of the belts 20, 22, 24 is looped over a pair of spaced apartrollers which are supported in fixed positions in any suitable manner.As shown, the forwardmost belt 20 is looped over rollers 30 and 32,whose shafts are journalled in suitable front end brackets 34 and 36secured to the sewing table 14. The center and rear belts are loopedover rollers 38,' 40 and 42, 44, respectively, whose shafts arejournalled in intermediate and rear end brackets 46 and 48,respectively. The table 14 and brackets 46 and 48 are mounted in anysuitable manner on a main frame 50 which rests on the floor 52. Theconveyor belts are synchronously driven at constant speed by a motordrive unit 54 and a chain drive linkage mounted on one side of theequipment. As best shown in FIGURE 2 the motor unit 54 is mounted on therear edge of the sewing machine table 14 and is provided with an outputshaft 56 which is directly coupled at 58 to the shaft of the rear roller32 of the front conveyor 20. The center conveyor 22 is driven from theroller 32 through a sprocket 60 thereon, a chain 62 and a sprocket 64 onthe roller 40. A second sprocket 66 on the roller 40l carries a secondchain 68 which drives the rear conveyor 24 through a sprocket 70 on theroller 44.

According to the principles of the present invention the stackingmechanism 26 includes a rotatable flip shaft 72 disposed out of the lineof travel of a garment comp@ nent 19 and provided with a plurality ofstacking arms which in operation lift a garment component from its lineof travel and flip it on to a suitable support, such as the stackingtable 28. In the embodiment of FIGURES 1 4 the axis of the flip shaft 72is disposed parallel to the lineof travel of the garment components orestablished by the conveyors 20, 22 and 24. As seen in FIGURES l and 2the shaft 72 is disposed in the same plane as the conveyors and isjournalled in brackets 74 which are secured to the frame member 48 onthe opposite side of the machine from the chain drive for the conveyors.The right-hand end portion of the shaft 72 as viewed in the drawingscarries two pairs of radially projecting stacker arms 76, 78 and 80, 82.The pairs are disposed at an angle of 180 to each other, and the membersof each pair lie in a common plane and are spaced apart along the axisof the shaft 72 a distance such that they can straddle either the endsof the center conveyor 22 or the sides of the stacking table 28, Thus,during clockwise rotation of the shaft 72 as viewed in FIGURE 3 theouter portions of a pair of arms will pass simultaneously upwardlythrough the two spaces at the ends of the center conveyor 22 and thendownwardly past the table 28. Rotation of the shaft 72 is effected by anendless timing belt 73 which is looped over a pulley 75 carried at therear end of the shaft 72.

As previously indicated the stacker arms 76, 78, 80 and 82 are movedthrough an arc of 180 each time a garment component 19 arrives in aposition in which it straddles the center conveyor 22. A drive mechanism83 for accomplishing this is illustrated in FIGURES l, 3 and 4 andschematically in FIGURE 5. As shown, the mechanism 83 includes aconstant speed motor drive unit 84 supported by the main frame 50 and achain drive for transmitting power to the ip shaft 72. The motor driveunit 84 has an output shaft 86 drivingly connected by means of a wormdrive 88 to a continuously driven main shaft 90 which is suitablyjournalled at its ends in the main frame 50. An electric clutch 92 and aspur gear 94 are mounted concentrically with the main shaft 90 in amanner such that the clutch 92 will effect a driving connection betweenthe shaft 90 and the gear 94 when engaged. When the clutch 92 isdisengaged, the shaft 90 rotates freely within the gear 94. A secondaryshaft 96 is mounted within the frame 50 below and parallel to the mainshaft 90 and is provided with a timing pulley 98 at its outer end. Thetiming belt 73 is looped over the pulley 98, over an idler pulley 102supported by the main frame 50, and over the pulley 75 on the flip shaft72.

A spur gear 104 fixed on the secondary shaft 96 intermediate its endsmeshes with the spur gear 94 on the main shaft 90. An electric brake106, supported by the main frame 50, is mounted concentrically with thesecondary shaft 96 for intermittently locking the latter againstrotation. A cam 108 on the shaft 96 between the brake 106 and the gear104 actuates a fixed niicroswitch 110 at each one-half revolution of theshaft 96 to thereby lock the brake 106 and disengage the clutch 92. Thisstops rotation of the shafts 72 and 96 until a sensing device 112 sensesthe arrival of the next garment component at the center conveyor 22 andsimultaneously releases the brake 106 and engages the clutch 92. Theclutch 92 and brake 106 are conventional devices and are controlledthrough a conventional control box 114.

The stacking machine 10 also includes a keeper arm 116 employed to reston top of any stack of garment components which has been built up on topof the stacking table 28. As best shown in FIGURES 2 and 3 the table 28is constructed as an elongated wooden bar, or the like, which projectslaterally from the main frame 50 and which has an exposed upper surface.If desired, the upper surface of the block may carry a fixed bracket 117as an aid in retaining garments thereon.

The keeper arm 116 is constructed in the general shape of an inverted Uand is pivoted at one end to the outer end of the table 28 for rotationin a vertical plane about a horizontal pivot pin 118. The free end ofthe arm 116 is provided with a horizontal extension 120 constructed ofrubber or the like which is shown as engaging a garment component 19draped over the top of the stacking table 2.8. The arm 116 is pivotableclockwise from the position shown in FIGURE 3 by means of asolenoid-operated rod 120 and linkage arrangement 122. The latterincludes a generally L-shaped link 124 pivotally connected at one end tothe arm 11.6 and at its other end to an end of the rod 120. The heel ofthe link 124 is pivotally connected to one end of a short, straight link126 whose other end is pivoted to the end of the table 28. The end ofthe rod 120 opposite the linkage arrangement 122 is bent at a rightangle to the remainder of the rod and is secured to a drive rod 128whose ends are connected to the plungers of a pair of spaced apartsolenoids 130 and 132. Energization of the up solenoid 130 pulls on thelower end of the rod 120 and causes the arm 116 to rise, whileenergization of the down solenoid 132 pushes the rod 120 and causes thearm 116 to return to its FIGURE 3 position. The solenodis are mounted inany suitable manner, as on a triangular bracket 134 which also supportsthe table y28.

The rod 120 is formed in two pieces 120a and 12011, joined together by aset collar 136 so that the effective length of the rod 120 can be variedto adjust the pivotal position of the arm 116.

The sensing device which is employed for recognizing the arrival of agarment component at the center Conveyor 22, and for providing a signalfor activating the stacking drive 83 upon this occurrence may be of anysuitable type. The device illustrated at 112 is a conventionalphotoelectric cell unit of the kind which produces a beam of light,projects the beam against a remote surface which reliects the beam tothe unit and senses any interruption ofthe beam. As seen in FIGURES l, 2and 3 the unit 112 is mounted above and intermediate the ends ofthe rearconveyor 24. A beam of light 138 (FIG- URES 3 and 5) is projecteddownwardly from a light generating portion 140 of the unit 112 towardthe surface of the upper run of the conveyor 24 at such an angle.- thatthe beam 138 which is reflected by the conveyor 24'- returns to aphotocell portion 142 of the unit 112. Upon interruption of the beam bythe leading edge of a garment component 19 the unit 112 together with asuitable elecf tric control circuit 144 (FIGURE 5) produces an elec--tric signal for initiating upward movement of the keeper arm 116 and aone-half revolution of the iip shaft 72' and consequent stacking of thegarment component 19 on the stacking table 28. In FIGURES 2 and 3 thecomponent which is on the conveyors 20, 22 and 24 is shown in a positionimmediately prior to its interruption of the light beam 138.

The position of the sensing unit 112 along the length of the rearconveyor 24 is selected so that the midpoint of a garment component 19is approximately at the midpoint of the center conveyor 22 when theleading edge of the component interrupts the light beam 138. By thisarrangement the stacker arms 76, i8 or 80, 82 will engage the component19 near its middle so that the component 19 will drape evenly over thearms with no tendency to slip off. The sensing unit 112 may be mountedso as to be adjustable along the length of the rear conveyor 24 tothereby accommodate the machine 1t) to processing garment components ofdifferent lengths. In the embodiment illustrated the unit 112 issupported by a nut 146 which is fixed against rotation and which iscarried on a threaded rod 148 extending parallel to and to one side ofthe rear conveyor 24. The rod 148 is journalled at its ends in brackets150 carried by the rear frame member 48 and is coupled to the outputshaft of a reversible motor 152 which is also supported from the framemember 48. The motor 152 is manually controlled to rotate the rod 148 ineither direction thereby moving the nut 146 and the sensing unit 112 toany desired position along the conveyor 24.

It will be understood that other sensing devices and drive mechanismsmay be employed for effecting intermittent rotation of the stacker arms76, 78 and 80, 82 upon arrival of a garment Component at the centerconveyor 22.

FIGURE 6 illustrates in simplified form a modified stacking machine 10'suitable for stacking garment components 19 of firmer, less slick fabricthan the components processed by the machine 10` of FIGURES 1-5. In theFIGURE 6 construction the natural stiffness of the components 19 isrelied on to maintain them in a sufllciently flat condition to bedelivered to and flipped by the stacker arms, two of which are :shown at78 and 82. As shown, the sewing machine table 14 is horizontally andvertically spaced from the stacking machine 10', and the components 19'are allowed to slide by gravity down a stationary inclined extension 154at the rear of the table 14. The flip shaft 72 is disposed rearwardly ofand below the lower end of the extension 154 and is braked in a positionsuch that one of its pairs of arms will receive the component as itslides oil" the extension 154. A stationary photocell sensing unit 112is positioned so as to be straddled by the arms during rotation and soas to sense the leading edge of the component 19'. In this arrangementthe sensing unit 112 is constructed to produce an activating signal forthe drive 83 when light from its beam producing element 158 is rellectedfrom the component 19 into its photocell element 160.

Operation The stacking machine 10 is placed in a condition to receiveand stack garment components 19 automatically by first energizing themotors 54 and 84, thereby placing the conveyors 20, 22 and 24 and themain drive shaft 98 (FIGURE 4) in continuons operation. As describedpreviously, the motor 54 drives the conveyors at constant speed throughthe sprocket and chain arrangement shown in FIGURE 2. An operator,sitting at the forward end of the sewing machine table 14, then performsa stitching operation on a garment component by manually guiding thecomponent under the sewing head of the sewing machine 18. As the leadingedge of a component 19 is discharged rearwardly by the sewing machine 18it is engaged by the upper run of the forward conveyor and pulledrearwardly thereby maintaining the fabric in a flattened condition. Whenthe trailing edge of the component 19 is released by the sewing machine18 the entire component is conveyed rearwardly in a flat condition. Theconveyor 20 operates at a high linear speed so that each garmentcomponent Will become spaced from the following one. As is conventionalin this type of stitching operation each garment component will beconnected by a thread chain to the subsequent component, and it will beassumed that the thread chain is cut either man- 6 ually orautomatically as each component leaves the sewing machine 18.

The garment component then rapidly passes from the forward conveyor 20to this center conveyor 22 and then to the rear conveyor 24 without anywrinkling or buckling. If desired, the rear conveyor 24 may be run at ahigher speed than the center conveyor 22 and the latter at a higherspeed than the forward conveyor 20, by appropriate selection of the sizeof the sprockets 64, 66 and 70, in order to increase the flatteningeffect on the garment component during its travel. During this periodthe sensing unit 112 Will be ineffective, because the beam of light 138will be continuously reflected from the surface of the conveyor 24 tothe photocell portion 142 of the unit 112. When the leading edge of acomponent 19 moves slightly rearwardly from the position illustrated inFIGURE 1 to the position illustrated in FIGURE 5 the light beam 138 willbe interrupted] and the flip shaft 72 will be rotated through 180through the agency of the sensing unit 112, the control circuit 144 andthe drive mechanism 83. The position of the sensing unit 112 along thelength of the rear conveyor 24 will have previously been adjusted byrotation of the threaded rod 148 so that approximately one-half of thegarment component 19 will have traversed the center conveyor 22 at thetime of interrupting the light beam 138. The midpoint of the garmentcomponent 19 will therefore be about midway between the stacker arms 76and 78 when the latter are rotated.

-Upon interruption of the light beam 138 by the garment component 19 thesensing unit 1.12 creates a signal which is employed to initiaterotation of the flip shaft 72 and simultaneously to raise the keeper arm116 away from the stacking table 28. More specifically, these operationsare effected by a suitable control circuit, illustrated at 144 in FIGURE5, which upon receiving the signal from the sensing unit 112 engages theelectric clutch 92, releases the brake 186 and energizes the up solenoid130. Energization of the latter rotates the keeper arm 116 clockwise asviewed in FIGURE 3. Engagement of the clutch 92 causes the normallystationary gear 94 to rotate with the continuously rotating shaft 92 andto transmit driving force to the shaft 96 through the gear 104. Sincethe brake 106 is released simultaneously, the Shaft 96 rotates anddrives the flip shaft 72 through the agency of the pulleys 98, 102 and72 and the belt 100.

The cam 108 on the shaft 96 is designed to actuate the microswitch 110after 180 of rotation. When actuated, the microswitch together with thecontrol circuit disengages the clutch 92 and applies the brake 106thereby bringing the shaft 92 and the flip shaft 72 to an abrupt halt.At the same time the up solenoid is de-energized and the down solenoid132 is energized to rotate the keeper arm 116 counterclockwise as viewedin FIG- URE 3. The flip shaft 72 and the keeper arm 116 are then inposition to be reactuated upon the next interruption of the light beam138.

Referring again to FIGURES 1-3 it will be seen that of rotation of theflip shaft 72 from the position shown in these figures will move thestacker arms 76 and 78 through an arc upwardly through the spaces at theends of the center conveyor 22 and then downwardly past the uppersurface of the table, thereby defining onehalf of a cylinder ofrotation. Since the pairs of arms 76, 78 and 80, 82 are angularly spacedapart 180, each pair will come to rest in the position previouslyoccupied by the other paid.

As previously described the garment component 19, at the moment ofrotation of the flip shaft 72, is straddling the center conveyor 22 andwill therefore be engaged intermediate its ends by the arms 76 and 78.Upon upward movement of the arms 76 and 78 the component 19 will belifted off the conveyors with the leading end of the component drapingover the arm 76 and the trailing end draping over the arm 78. Thecomponent 19 must, of course, be of sufficient length that the Weight ofthe draped portions will prevent the entire component from collapsinginto the space between the arms 76 and 78. In addition, the movement ofthe arms 76 and 78 must be sufficiently rapid to deposit the component19 on top of the table 23 before it can slip off the arms.

By the time the arms 76 and 78 have moved into proximity with the table28 the keeper arm 116v will have pivoted out of the line of travel ofthe arms so that the component, now illustrated at 21, Will be depositedin an inverted position on top of the table 28. The keeper arm 1116 willthen descend and clamp the component 21 and all previously stackedcomponents between the table top and the extension 120. The keeper arm.116 is sufficiently fiexible that it will bend to accommodate a stackof components 21 of considerable height. Ultimately, of course, thestack is manually removed from the table 28 by the operator andtransferred to another station.

The operation of the modified machine 10 of FIGURE 6 is similar to thatof the machine i0. Garment components 19', assuming that any threadchain between adjacent components becomes cut after leaving the sewingmachine 18', slide by gravity down the fixed inclined extension 154 andinto a draped position on a pair of spaced arms one of which is shown at82. The leading edge of the garment component 19 then reflects a beam oflight from the element 158 to the element 160 of the sensing unit 112'whereupon the flip shaft '72 is rotated 180 counterclockwise. Thegarment component 19 is thereby moved through an arc and draped over thetop of the ta'ble 28', the other pair of arms simultaneously moving intoa position to receive another garment component 19. This arrangementrequires that the components 19' have considerable stiffness, Ibecauseif too flexible they would tend to bunch while sliding into position andwould thereby fail to drape properly over the arms.

It will be understood that modifications of the embodiments disclosedherein may be made without departing from the scope of the inventionwhich is defined by the appended claims. It will be understood, forexample, that a single set of stacker arms or more than two sets of armsmay be employed provided that the drive system is constructed to rotatethe sets through arcs of such length that only one set sweeps the lineof travel of the Workpiece during each arcuate movement.

What is claimed is:

1. An automatic stacking machine for stacking liexible workpieces suchas garment components and the like comprising: movable stacking meansfor engaging one face of a workpiece and for subsequently depositing theworkpiece on the exposed end of a stack of previously handled workpieceswith the other face in contact with said exposed end, said stackingmeans including a pair of generally parallel coextensive arms mounted inspaced apart relationship for simultaneous rotation about a common axisthrough one end of said arms; a stationary workpiece receiving standhaving a receiving surface at least partially Within the cylinder ofrevolution defined by rotation of said arms, said receiving surfacehaving a dimension in the direction of said axis of rotation which isless than the minimum distance between said arms whereby during rotationsaid arms can sweep past said surface without engaging the same; anddrive means -for intermittently rotating said arms through apredetermined arc past said receiving surface remote therefrom wherebysaid arms may engage one surface of a workpiece at said remote positionand cause the workpiece to drape over said arms and whereby theworkpiece Will be deposited with its other face in contact with saidreceiving surface or with the exposed end of a stack of workpieces onsaid receiving surface during sweeping of said arms past said receivingsurface 2. An automatic stacking machine for handling and stacking eachof a plurality of flexible workpieces such as garment components and thelike moving in longitudinally spaced apart relationship along a line oftravel, said machine comprising: a pair of generally parallelcoextensive arms each having an inner end mounted for simul-A taneousrotation and an outer end 4portion remote from the axis of rotation,said arms being disposed adjacent the line of travel of the workpiecesin a position such that said outer end portions of the arms can sweeptransversely through the line of travel when said arms are rotated;means defining a stationary workpiece-receiving surface having adimension less than the minimum distance between said outer endportions, said receiving surface being disposed in a position in whichit lies between said outer end portions during part of one revolution ofsaid arms; and motor drive and control means for said arms includingmeans responsive to the arrival of a workpiece at a predeterminedposition along the line of travel lfor rotating said arms through apredetermined arc in a direction such that said outer end portions ofsaid arms sweep into the line of travel from below and for subsequentlystopping said arms after said outer end portions have swept past saidworkpiece-receiving surface whereby the workpiece is lifted out of theline of travel by engagement of said outer end portions with the lowerface of the workpiece and is subsequently deposited on said receivingsurface or on the exposed end of a stack of workpieces on said surfacewith the upper face of the workpiece in engagement with said surface orwith the exposed end.

3. Apparatus as in claim 2 wherein said drive and control means includesa continuously running motor, edgeresponsive means for detecting thearrival of the leading edge of the workpiece at the predeterminedposition and for effecting a driving connection between said motor andsaid arms upon detection of the workpiece edge, said drive and controlmeans further including means for disconnecting said driving connectionwhen said arms have rotated through a predetermined arc past saidreceiving surface.

4. Apparatus as in claim 2 wherein said arms are mounted radially on acommon shaft, said shaft being disposed parallel to the line of travelof the workpieces.

5. Apparatus as in claim 2 wherein there are a plurality of pairs ofarms extending radially from a common axis of rotation and wherein saiddrive and control means upon arrival of a workpiece at the predeterminedposition rotates all of said arms simultaneously through an arc of suchlength that only `one pair of arms sweeps the line of travel and saidreceiving surface during each movement of said arms.

6. Apparatus as in claim 2 including an endless conveyor having an upperrun determining the line of travel of the workpieces, said upper runbeing of lesser length than the minimum distance between said outer endportions of said arms and being disposed in a plane parallel to the axisof rotation of said arms whereby during rotation of said arms said outerend portions sweep past both ends of said upper run and lift off aworkpiece which straddles said run.

7. Apparatus as in claim 2 including three endless conveyors havingupper runs disposed in end-to-end relationship and determining the lineof travel of the workpieces, the end conveyors being slightly spacedfrom the center conveyor in the plane of said conveyors so as to permitsaid outer end portions of said pair of arms to pass between each of theend conveyors and the center conveyor, the upper run of the centerconveyor being of lesser length than the minimum distance between saidouter end portions of said arms and being disposed in a plane parallelto the axis of rotation of said arms whereby during rotation of saidarms said outer end portions sweep past both ends of the upper run ofsaid Center conveyor and lift off a workpiece straddling said run.

S. An automatic stacking machine for sequentially receiving flexibleworkpieces, particularly slick garment components, from a sewing machineand for automatically stacking the workpieces one on top of another,said machine comprising: three continuously driven endless conveyorsdisposed in longitudinally spaced apart end-to-end relationship andhaving upper runs which carry the workpieces along a line of travelwhile maintaining them in a flat condition, the upper run of the centerconveyor being of lesser length than a workpiece whereby a workpieceduring a portion of its movement along the line of travel will overliethe whole of the upper run of the center conveyor and Will overlap theends of the upper runs of the other two conveyors; a rotatable shaftdisposed to one side of said conveyors and extending parallel to theupper run of said center conveyor; a pair of arms extending radiallyfrom said shaft and spaced apart along the shaft in an axial direction,the length and spacing of said arms being such they pass through thespaces between the center conveyor and the other two conveyors uponrotation of said shaft; a stacking table disposed on the other side ofsaid shaft from said conveyors in a position opposite said centerconveyor, the dimension of said table in the direction of the axis ofsaid shaft being less than the distance between said arms, said tablebeing disposed so as to lie between said arms during a portion of acomplete revolution of said shaft whereby intermittent rotation of saidshaft in a direction to raise said arms past the ends of said centerconveyor lifts a workpiece from said conveyors, drapes it over saidarms, carries it through an arc and drapes it over the top of said tableor over the top of a workpiece which has been previously deposited.

9. Apparatus as in clairn 8 including a plurality of pairs of armscarried by said shaft at the same axial position and at equal angularintervals and further including intermittent drive means for said shaftfor intermittently rotating said shaft through equal arcs 4during eachof which only one pair of arms is raised past said center conveyor andpast said table. g

References Cited UNITED STATES PATENTS 1,027,283 5/1912 Scott 271-66EDWARD A. SROKA, Primary Examiner.

1. AN AUTOMATIC STACKING MACHINE FOR STACKING FLEXIBLE WORKPIECES SUCHAS GARMENT COMPONENTS AND THE LIKE COMPRISING: MOVABLE STACKING MEANSFOR ENGAGING ONE FACE OF A WORKPIECE AND FOR SUBSEQUENTLY DEPOSITING THEWORKPIECE ON THE EXPOSED END OF A STACK OF PREVIOUSLY HANDLED WORKPIECESWITH THE OTHER FACE IN CONTACT WITH SAID EXPOSED END, SAID STACKINGMEANS INCLUDING A PAIR OF GENERALLY PARALLEL COEXTENSIVE ARMS MOUNTED INSPACED APART RELATIONSHIP FOR SIMULTANEOUS ROTATION ABOUT A COMMON AXISTHROUGH ONE END OF SAID ARMS; A STATIONARY WORKPIECE RECEIVING STANDHAVING A RECEIVING SURFACE AT LEAST PARTIALLY WITHIN THE CYLINDER OFREVOLUTION DEFINED BY ROTATION OF SAID ARMS, SAID RECEIVING SURFACEHAVING A DIMENSION IN THE DIRECTION OF SAID AXIS OF ROTATION WHICH ISLESS THAN THE MINIMUM DISTANCE BETWEEN SAID ARMS WHEREBY DURING ROTATIONSAID ARMS CAN SWEEP PAST SAID SURFACE WITHOUT ENGAGING THE SAME; ANDDRIVE MEANS FOR